Proposed Amendments to Air Toxics Standards for Stationary Combustion Turbines

FACT SHEET
Proposed Amendments to Air Toxics Standards for Stationary Combustion Turbines
ACTION
• On April 2, 2019, the U.S. Environmental Protection Agency (EPA) proposed to amend
the 2004 National Emission Standards for Hazardous Air Pollutants (NESHAP) for
Stationary Combustion Turbines.
• EPA issued the air toxics standards for Stationary Combustion Turbines on March 5,
2004. The rule applies to stationary combustion turbines located at major sources of
hazardous air pollutants (HAP).
• Following a residual risk and technology review conducted under the Clean Air Act
(CAA), EPA is proposing to determine that risks from the source category are acceptable
and that no new cost-effective controls are available.
• EPA is also proposing to:
o Revise requirements for periods of startup, shutdown and malfunction (SSM) to
be consistent with recent court decisions;
o Require electronic reporting of performance test results and compliance reports;
and
o Remove the stay of the standards for new gas-fired stationary combustion
turbines.
• EPA will accept comment on the proposed amendments for 45 days after publication in
the Federal Register.
RESIDUAL RISK ASSESSMENT
• The CAA requires EPA to assess the risk remaining after application of the final air toxics
emissions standard. This is known as a residual risk assessment.
• Based on the completed risk assessment, available health information and associated
uncertainties, EPA determined risks from the Stationary Combustion Turbine source
category are acceptable with an ample margin of safety to protect public health.
• Stationary combustion turbines are typically located at power plants, compressor
stations, landfills and industrial facilities such as chemical plants.
• EPA assessed facility-wide risks and found that the maximum facility-wide cancer risk is
2,000-in-l million, caused by ethylene oxide emissions from a variety of industrial
processes which are not part of the Stationary Combustion Turbine source category. In
late 2016, EPA updated a risk value for ethylene oxide which was used in this
assessment.
• EPA will evaluate these facility-wide estimated emissions and risks further working with
industry and state, local and tribal air agencies in a two-pronged approach to address
ethylene oxide emissions:
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1. Review and, as appropriate, revise CAA regulations for facilities that emit ethylene
oxide - starting with air toxics emissions standards for miscellaneous organic
chemical manufacturing facilities and commercial sterilizers; and
2. Conduct site-specific risk assessments and, as necessary, implement emission
control strategies for targeted high-risk facilities.
TECHNOLOGY REVIEW
• The CAA requires EPA to assess, review and revise air toxics standards, as necessary,
considering developments in practices, processes and control technologies.
• The technology review of the standards for stationary combustion turbines did not
identify any developments that would further reduce HAP emissions beyond the original
NESHAP.
BACKGROUND
• The CAA requires EPA to regulate toxic air pollutants, also known as air toxics, from
categories of industrial facilities in two phases.
• The first phase is "technology-based," where EPA develops standards for controlling the
emissions of air toxics from sources in an industry group or "source category." These
maximum achievable control technology (MACT) standards are based on emissions
levels that are already being achieved by the best-controlled and lower-emitting sources
in a source category.
• Within 8 years of setting the MACT standards, the CAA directs EPA to assess the
remaining health risks from each source category to determine whether the MACT
standards protect public health with an ample margin of safety and protect against
adverse environmental effects. This second phase is a "risk-based" approach called
residual risk. Here, EPA must determine whether more health-protective standards are
necessary.
• Also, every 8 years after setting MACT standards, the CAA requires EPA to review and
revise the standards, if necessary, to account for improvements in air pollution controls
and/or prevention.
HOW TO COMMENT
• The EPA will accept comment on the proposal for 45 days after publication in the
Federal Register. Comments, identified by Docket ID No. EPA-HQ-OAR-2017-0688, may
be submitted by one of the following methods:
o Go to https://www.regulations.gov and follow the online instructions for
submitting comments,
o Send comments by email to: a-and-r-Docket@epa.gov, Attention Docket ID No.
EPA-HQ- OAR-2017-0688.
o Fax your comments to: (202) 566-9744, Attention Docket ID. No. EPA-HQ-OAR-
2017-0688.
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o Mail your comments to: EPA Docket Center, Environmental Protection Agency,
Mail Code: 28221T, 1200 Pennsylvania Ave., NW, Washington, DC 20460,
Attention Docket ID. No. EPA-HQ-OAR-2017-0688.
o Deliver comments in person to: EPA Docket Center, 1301 Constitution Ave., NW,
Room 3334, Washington, DC. Note: In person deliveries (including courier
deliveries) are only accepted during the Docket's normal hours of operation.
Special arrangements should be made for deliveries of boxed information.
FOR MORE INFORMATION
• Interested parties can download a copy of the proposed rule notice from EPA's website
at the following address: https://www.epa.gov/stationary-sources-air-
pollution/stationary-combustion-turbines-national-emission-standards.
• Today's action and other background information are also available either electronically
at https://www.regulations.gov. EPA's electronic public docket and comment system, or
in hard copy at the EPA Docket Center's Public Reading Room.
o The Public Reading Room is located at EPA Headquarters Library, room number
3334 in the EPA WJC West Building, 1301 Constitution Ave., NW, Washington,
DC. Hours of operation are 8:30 a.m. to 4:30 p.m. Eastern Standard Time,
Monday through Friday, excluding Federal holidays,
o Visitors are required to show photographic identification, pass through a metal
detector and sign the EPA visitor log. All visitor materials will be processed
through an X-ray machine as well. Visitors will be provided a badge that must be
visible at all times.
o Materials for this proposed action can be accessed using Docket ID No. EPA-HQ-
OAR-2017-0688.
• For further technical information about the rule, contact Melanie King, EPA's Office of
Air Quality Planning and Standards, at (919) 541-2469 or king.melanie@epa.gov.
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